BYOV: bring your own vegetables: Winter Sowing Seeds

Sunday, June 9, 2019

Winter Sowing - Sugar Snap Peas, Kale, Kohlrabi, and Chives

While a previous post may regale you with the success of spring-planting fall bulbs...winter sowing in spring will not be quite as successful.

Don't get me wrong, the winter sowing method in used-up milk & fruit jugs worked gangbusters. It's just that you need to plant in February/March so you have seedlings ready to plant in May. My second raised bed still isn't ready due to a garden injury, but I figured I'd start my seeds anyways. Not sure how I stumbled on TheReidHomestead's post on Winter Sowing 101, but it seemed like an approachable enough avenue of attack - and it was!

Basically, you cut around a cleaned container around 4" from the bottom, leaving 1" uncut to use as a hinge. Cut some drainage holes in the bottom and the side/bottoms, and maybe a couple optional holes at the top of the container to let some additional moisture escape. You then fill the bottom of the carton with 2-3" of potting soil (I use Happy Frog). Now you have a mini greenhouse!

Next you plant the seeds a little more shallowly than suggested on the package. The best plants for this approach are the kind successful in early spring and a little hardy in cold temperatures. It's best to start this in winter (sprouting won't occur until much later). The greenhouse will buffer the seeds from the worst weather, but many plants actually prefer a little coldness action. You won't have to do anything except ignore the mini-greenhouses until the seedlings get a few inches tall.

Use duct tape to seal around the mid-carton cut, and remove the lid of the container. Place the mini-greenhouse where it will get sun and rain/snow, but where the wind won't knock it over.

Modifying Mini-Greenhouses for Winter Sowing with Twist-tie Closure

As the seedlings sprout and get larger, you'll need to open the top half on hot days, so the seedlings don't get fried. At this point, you'll probably want to water them. As you get close to transplanting day, it's a good idea to occasionally open the top half of the carton to give the plants some real world exposure. I found myself opening and closing these quite a bit (the consequences of sowing in spring, not winter), and this wore the duct tape out pretty quickly. So I modified my containers to have a twist-tie closure which is considerably more reusable. Not quite as critter proof, but it should be okay for spring planting in mini greenhouses.

Winter Sown Seedlings (in spring), 2-3 weeks growth

Top row - sugar snap peas (planted May 9 & May 17)
Bottom left - purple and white kohlrabi - planted May ~17
Bottom right - mixed kale - planted May 9
Either way, this approach worked so much better then trying to start seeds in egg cartons indoors. And this way, no hardening-off is necessary!